Spray nozzles for generating streams of liquid are well known as seen from U.S. Pat. No. 4,854,504 which describes a resin being emitted from a nozzle having an oval opening in the center and streams of catalyst impinging on the resin stream from angles on each side of the oval opening. In addition, air control nozzles are located on either side of the catalyst openings and these also impinge on the resin stream after the catalyst has been mixed with the resin stream. Other patents showing an external mix spraying system are U.S. Pat. Nos. 4,824,017, 5,085,370 and 5,067,515. The latter two show multi-fluid spray guns in which a resin catalyst is mixed in externally. Other spray guns are shown in U.S. Pat. Nos. 4,948,048 and 4,925,104. A more recent U.S. Pat. No. 5,704,548, shows another type of spray nozzle.
In the commercial literature it is well known to design spray nozzles with elliptical openings or with rows of parallel openings to obtain different types of spray patterns. A common spray pattern achieved with a single circular opening is cone shaped. Although these nozzles are useful for their particular purposes, no one to date has developed a nozzle that can produce a triangular type pattern from two solid streams of liquid absent any atomization or obstruction to the stream pattern after leaving the nozzle head. An improved nozzle is needed for providing a broad triangular pattern of liquid for use with fire hoses, building sprinklers, agricultural headers, car wash nozzles and for spraying resins over molds to create various devices such as boat hulls, bath tubs, etc. This latter use needs to be carried out with minimum contamination to the environment.
The open contact molding process using polyester resins employs nozzles having at least two series of parallel openings and is known as a FLOCOAT nozzle. This nozzle creates several streams in a fan-like spray pattern and reduces noxious emissions to the atmosphere. Unfortunately, the size limitation of the nozzle openings of 0.010 to 0.030 inches causes constant plugging in some applications. Therefore, FLOCOAT nozzles cannot be used in the tub/shower and other industries where it is necessary to add fillers such as calcium sulfate, calcium carbonate and aluminum trihydrate to the resin for fire retardency as well as economics. These fillers are fairly large in size and tend to agglomerate resulting in constant tip plugging when a FLOCOAT nozzle is used. The gaps created in the FLOCOAT pattern also eliminate it from being used to apply polyester gelcoat. This is typically the first coating applied to a mold when producing a fiberglass part. Its primary purpose is to provide shielding as well as a cosmetic finish and it is typically applied in a thin film of between 0.010 to 0.040 inches. The FLOCOAT nozzle does not provide uniform coverage in this thickness range and therefore is unacceptable for this application. It is for these reasons that these two very large segments of the fiberglass industry; i.e., filled resins and gelcoats, cannot utilize FLOCOAT technology to reduce emissions.
The tub/shower and related industries consume the most polyester resins and has the greatest potential of emitting styrene from the spraying equipment used. Styrene is emitted during the application stage when a catalyzed gelcoat or resin is applied to the surface of an open mold. The Environmental Protection Agency (EPA) of the U.S. Government is actively seeking ways to limit these styrene emissions. Additional standards for the reinforced plastics and composite source category and boat building source category are scheduled to be promulgated by the EPA on Nov. 15, 2000.
Based on recent EPA reports, in their gelcoat experiments, volatile organic compounds could be reduced if an improved fan pattern for spray nozzles could be developed. The present invention responds to that need.